**Gristleizer Build Report!!!** Sound clips for normal people inside!

[thedefog]

Hi all! Just joined diy stompboxes as I am building the Gristleizer too. I have a few problems with the wiring of the rotary pot. One of the positions appears to do nothing at all to the sound.  Just wondering if a consensus has been reached as to the correct diagram of what to be wired where. There appears to be conflicting diagrams about A1 B1, A4 B1 etc. Anyone out there able to clarify this for us wannabe TG freaks?

Hey there, and welcome to the forum!

A4 to B1 solved that issue for me. The square wave function won't work (last position on the rotary) if this jumper connection isn't made. Good luck!

Nevermind what I wrote there. I solve my problem, as well as yours.

http://gaussmarkov.net/layouts/gristle/gristle-perf.png

Just follow the wiring diagram on the gaussmarkov page. Ignore the PDF wiring and you should be fine. I now have no issues with the distorting volume or anything anymore with mine following this wiring.

[-minus]

Nevermind what I wrote there. I solve my problem, as well as yours.

http://gaussmarkov.net/layouts/gristle/gristle-perf.png

Just follow the wiring diagram on the gaussmarkov page. Ignore the PDF wiring and you should be fine. I now have no issues with the distorting volume or anything anymore with mine following this wiring.

Thanks thedefog! I have rewired the rotary pot. Had some success...

Now I know this is not correct as following the layout, but by wiring A3 and A4 together, as well as A4 to B1, I am getting some quite 'throbbing' sounds on this setting. All my pots are external at this stage. Got a trim pot for SHAPE today. This pot seems to do nothing in my mind. However, with my 'bent' A3 to A4 mod, using the OFFSET and SPEED pot, I am getting some very nice undulating sounds... if you like that type of droney thing. I'm plugging an Atari Punk Console into it to get a single tone.

I'm almost thinking about leaving it as this, as this hack seems to be the mode I keep coming back to. And no, I'm not sure why this is. I have little experience with this DIY stuff and am a solder-by-numbers person at this early stage.

I wouldn't mind slowing it down further though. Perhaps increasing a cap value somewhere?

[thedefog]

Nevermind what I wrote there. I solve my problem, as well as yours.

http://gaussmarkov.net/layouts/gristle/gristle-perf.png

Just follow the wiring diagram on the gaussmarkov page. Ignore the PDF wiring and you should be fine. I now have no issues with the distorting volume or anything anymore with mine following this wiring.

Thanks thedefog! I have rewired the rotary pot. Had some success...

Now I know this is not correct as following the layout, but by wiring A3 and A4 together, as well as A4 to B1, I am getting some quite 'throbbing' sounds on this setting. All my pots are external at this stage. Got a trim pot for SHAPE today. This pot seems to do nothing in my mind. However, with my 'bent' A3 to A4 mod, using the OFFSET and SPEED pot, I am getting some very nice undulating sounds... if you like that type of droney thing. I'm plugging an Atari Punk Console into it to get a single tone.

I'm almost thinking about leaving it as this, as this hack seems to be the mode I keep coming back to. And no, I'm not sure why this is. I have little experience with this DIY stuff and am a solder-by-numbers person at this early stage.

I wouldn't mind slowing it down further though. Perhaps increasing a cap value somewhere?

That's odd that you have a difference by wiring both of them together. I didn't notice any difference when A3-A4 were jumpered, so I disconnected them.

On another note, I experimented more (during daytime hours when I could actually turn my amp up) and still noticed the distortion in the circuit. I'm guessing the 741 buffer stage is amplifying it a bit too much for a guitar. This is even with the input impedance mod, changing R19 to 1M, along with increasing R21 to 1M and R20 to 100K. I also changed C7 to a .33uf cap to allow a bit more low end through the input.

I am guessing my R22 value is off, or TR2 was damaged due to it being connected to the negative 9v initially. I'm going to check these and post an update.

And one more thing, I'm getting a bit of noise when turning the pot for volume. Is a .068uf as a coupling cap too low a value to keep the DC voltage from the pot? I'm going to experiment with that as well. Any insight would be valuable here.

[-minus]

Hmmmm... Cant really help with coupling cap query. Too much of a novice really. This seems to be a tricky circuit for some reason. I like Throbbing Gristle, but apart from saying "Throbbing Gristle" every time someone asks what that box is, this has been a bit of a let down. I don't play guitar so I probably have different criteria as to what sounds great.

I'm thinking of mucking around with this board some more and taking it away from its initial intention. Might try substituting some resistor and capacitor values here and there and see what happens. I didn't notice anything significant from the triangle selection. Ramp and saw seem to work, although it sounds very subtle. Bit of a legendary effect from a legendary group, but not sure if it has been worth the bother.

[deathfaces]

I'm still debugging mine. Hoping for a breakthrough soon.

[thedefog]

I tried higher R22 values, as well as replacing the transistor as I had mentioned before, but it didn't remedy the problem. Increasing R22 causes the effect to not work properly, due to it being designed to have a high gain output. I think the best solution to this would be to use an opamp with a lower gain than the 741 for the input buffer stage. Perhaps something with a 10x buffer factor rather than like 100x would tame it, but then a few other changes would probably have to be made in order to make the circuit behave correctly. I'm going to experiment a bit with this and post what I find.

[deathfaces]

I did some probing and found that the signal went into ic4 just fine, but then it was mixed with a buzzing sound on its way out.  Could this be a bad ic? the lfo part of the circuit sounds like what i'll assume it is supposed to sound like (for the time being).  When i probed tr2 i got the buzzing from ic4, but no lfo sounds.  advice? thanks

[grinnin]

Hi,

I was thinking about building a Gristleizer, but using it for more noise-based stuff.  Are there any more thoughts on getting it to self-oscilate?

Ie. ~4:05 in this video http://www.youtube.com/watch?v=gV597br-oq8&feature=related

[thedefog]

I did some probing and found that the signal went into ic4 just fine, but then it was mixed with a buzzing sound on its way out.  Could this be a bad ic? the lfo part of the circuit sounds like what i'll assume it is supposed to sound like (for the time being).  When i probed tr2 i got the buzzing from ic4, but no lfo sounds.  advice? thanks

I doubt the IC went bad. 741s are pretty hard to fry. I have yet to do so in 10 years of doing this stuff, nor have I replaced a bad one anywhere on anything I've repaired.

You are building yours from the PCB board layout and not perf or vero, correct? Is the Buzzing regardless of whether you play a note? And is it like a ground noise buzz, or a higher pitched thing? You could just be hearing the LFO with the speed cranked up all the way.

[thedefog]

Hi,

I was thinking about building a Gristleizer, but using it for more noise-based stuff.  Are there any more thoughts on getting it to self-oscilate?

Ie. ~4:05 in this video http://www.youtube.com/watch?v=gV597br-oq8&feature=related

Hey there,

What Taylor wrote works:
"Seems like feedback from the output of IC5 to its + input would make it oscillate, no? Add a pot to control amount of feedback..."

I wired it up, but found it not to be so useful for me. But different strokes...

[deathfaces]

i got it working well enough, i replaced the ic's and trannies. the bias pot only seems to do anything when its turned to at least 6 o clock, so theres something funny there.  the clock noise just seems to be part of the circuit, judging by jacobs demos, or maybe mine isnt gating enough between the oscillator and input signal. either or, it'll do enough for me to have fun with it, so on to something new.

[thedefog]

i got it working well enough, i replaced the ic's and trannies. the bias pot only seems to do anything when its turned to at least 6 o clock, so theres something funny there.  the clock noise just seems to be part of the circuit, judging by jacobs demos, or maybe mine isnt gating enough between the oscillator and input signal. either or, it'll do enough for me to have fun with it, so on to something new.

I notice minimal clock noise in my build. I only really hear it on the square wave output, and that is just part of the circuit. If you hear it in different modes, there may yet be something off in your build. Post some samples of it on here and maybe I'll be able to help you out some.

[StonedDiplodocus]

Hi everybody !

I have this pedal kit but not possible to find a schematic to solder : DC, 3PDT, Jacks and PCB together...  I tried different ways and everytime it didn't work.

Can you help me please.

So I join a picture of my current stuf :



Have a nice day, Anthony.

[bluebunny]

I've only had one coffee this morning (so not truly awake yet...), but it looks to me like you're shorting the power when the switch is "up"?  (I've not got as far as working out what's going on when it's "down".)  Go to Tonepad and check out their wiring diagrams.  There are other schemes out there, but I've been using #3 and #5 from day one with no problems.